Uni-directional Razors. Modern conventional razors are typically made with either one or a pair of parallel strip-like razor blades secured upon the head of the razor. A handle extends from the head. The user holds the handle and ordinarily scrapes or moves the head in one direction along the skin so the blade or blades will cut the hair. After each movement in one direction, when the stroke is completed, the user lifts the razor and brings it back to a point near the original starting position for a second stroke in the same direction. Thus, conventional razors are uni-directional in operation.
Razors have also been made in which the head holds a single flat safety razor blade with two sharpened blade edges extending in opposite directions. These older style of razors have their blade edges spaced apart on opposite sides of the head, and angled so that they are and operate so as uni-directional devices. That is, the first blade edge is used until dull or filled with lather or cut hairs. Then the user manually turns the razor 180 degrees to present the opposite blade edge toward the skin. Such a single replaceable razor blade having two sharpened edges and mounted within a head of a razor that can be opened and closed was at one time very common, and it provided the user with twice the blade life, i.e., once for each sharp edge in uni-directional shaving.
Replaceable Cartridge Razors. Many conventional razors used for shaving have a handle or hand grip structure with means for securing a replaceable razor blade cartridge to it. These cartridge razor systems are desirable, in that a more expensive, ergonomic permanent handle, which can be reused thousands of times, can be provided and used in conjunction with a much less expensive replaceable cartridge containing the razor blades. The blades in such cartridges dull fairly rapidly with use. Thus they are frequently replaced, typically after just a dozen or less shaves. A variety of techniques and cartridge structures have been developed to allow the entire razor head to be readily replaced by the user of the razor.
Conventional Razor Head Constructions. Conventional safety razors typically comprise a guard or deck member and a cap member between which the razor blade or blades are sandwiched when the razor is ready for use. The handle, the guard member and cap member traditionally are all fixed relative to one another. The razors may be provided with a single or double-edged blades. In recent decades, the entire shaving unit or head has been made to be disposable.
A conventional modern razor cartridge typically has a blade seat having formed thereon a guard bar for smoothing the skin adjacent to the cutting edge or edges of the razor blade during shaving. The blade seat may include a channel which can be used to re-load the cartridge if the cartridge is reusable. A cap is provided to complete the main supporting structure of the razor cartridge. The blades are often retained by the passing of plastic pins through holes in the blades and then passing the pins into a heading which forms part of the cap. In this manner, the cap holds the blade or blades in place. The cap typically is pinned, fused, cemented or otherwise bonded together with the blade seat structure and captivates the blade or blades, and any spacers between them.
Wet Razors With Pairs of Blades. In recent years, almost every new wet razor blade system has a pair of parallel strip-like razor blades positioned closely to one another.
These parallel-blade constructions are typically used in razor cartridges that are disposable. The handle may also be disposable or it may be essentially permanent and meant to be re-used with many cartridges. In many of these systems, the pair of blades is encased in a razor head or cartridge which provides a fixed orientation of the blades to the skin through the use of leading, trailing and glide surfaces which define a working plane of the razor head. These various surfaces of the head all bear against the skin being shaved, and thus ensure the sharpened edges of the blade strips are presented at the proper angle to skin being shaved.
Guards For Blade Corners. The sharpened corners of the razor blade strips are guarded by the configuration of the head or cartridge structure for the safety of the user, so the corners do not cut the skin. The head often has an elongated narrow configuration to provide the user with the ability to shave the skin under the chin and nose and wherever the contours of the face are changing rapidly.
Staggered Double-Edged Blade Sets. U.S. Pat. No. 4,470,067 to Trotta discloses a double-edged blade configuration in a razor head. It is said to achieve a desired geometrical relationship between the leading and following cutting edges of the blades so that both are successively active with respect to hair elements being cut during a single shaving stroke. The razor's guard structure is disposed in fixed relation to the cutting edges to define desired relationships including a desired "blade tangent angle", and a preferred "exposure" and "span" and provides definitions for these terms. The platform member includes a back portion upstanding from the blade support portion. The guard and back portions define parallel opposite lengthwise edges of the platform member. As such, they define a single "working plane" which bears against the skin and controls the angle at which the sharpened edges of the blades are allowed to bear against a section of the skin to be shaved as the blade is moved in a single direction.
Pivotal Head Razors. Razors which have a fixed relationship between the head and the handle require considerable maneuvering in order to maintain the shaving unit at its optimum attitude on the shaver's face, particularly when negotiating areas such as the jaw line, where there are rapid changes in facial contour. To provide improved shaving characteristics, many razors have been provided with a pivotable head or cartridge, which is preferred by some users of manual safety razors.
In such a pivoting head or cartridge structure, the portion of the handle nearest the cartridge typically includes one or two spring-loaded mechanisms. The first is used to return the pivoting head to its center or at-rest position. The second is provided if the razor has a removable cartridge. In such case, the cartridge is typically held onto the handle by two pivot pins or bearing surfaces which engage in an interlocking manner with complementary sockets or arcuate slot structures located on the bottom of the cartridge. Since the handle can be re-used over and over, it is more economical to equip the essentially permanent handle with a more expensive mechanism for providing this spring-loaded pivoting, attachment structure than could be economically built into the disposable cartridge which is frequently replaced. This approach results in a cartridge having fewer spring-loaded components resident on it, thus reducing its cost.
Pivots Using Pins. To avoid lengthening the razor's head, pivoting arrangements located on the underside of the shaving unit or head away from the blades have been devised. An example is found in U.S. Pat. No. 4,094,063 to Trotta, which discloses a razor including a handle and shaving unit or head with the upper end of the handle including means for pivotally mounting the shaving unit so that the unit is free to pivot upon the handle during a shaving operation. The handle is a one-piece plastic molding and has means for biasing the pivotally movable shaving unit towards a central position. The connection between the upper end of the handle and the head is made through pivot pins directed axially inwardly. A leaf spring and stop blocks are provided for returning the head to an at-rest center position.
Pivots Using Shell Bearings. Another advance has been the use of juxtaposed, spaced, inner and outer, arcuate bearing segments and cooperating hollow shaft segments (also called guide rails) which are received into bearing engagement with the inner and outer bearing segments. The interengaged bearing segments and shaft segment define an axis of rotation for the shaving head that is located immediately adjacent the active elements or blades of the shaving system. This axis extends parallel to the cutting edges of the blades. In other words, each set forms an interengaged flange and groove elements with the end of the flange elements cooperating with the base of the groove elements in a thrust bearing relation. In use, the shaving unit is thus pivotally positioned along the skin so its cutting edges are parallel to the pivotal axis formed by the shell bearing members. An example of this approach is found in U.S. Pat. No. 3,935,639 to Terry et al. The Terry razor also includes a spring that acts between the handle and support member to bias the support member towards a middle position of pivotable adjustment relative to the handle.
Self-Lubricating Glide or Shaving Assist Strips. Modern razors often have a solid water-soluble shaving assistance or glide strip to provide a lubricant, whisker softener, razor cleaner, medicinal agent, cosmetic agent or a combination of the above as part of the disposable cartridge or razor itself. Such shaving aids are thus embedded in or formed as part of the glide strip which typically is affixed in the vicinity of the working plane of the razor, often in close proximity to the working edges of the blades. The shaving aid strip may be a shave-aiding agent combined with a solid, water-soluble micro-encapsulating or micro-porous structure which retains the agent. The strip can be the agent itself when it is a water-soluble solid. Exemplary materials constituting shaving aid strips are described in U.S. Pat. No. 4,170,821 to Booth, which is hereby incorporated by reference.
Flexible Razors. Flexible razor blade cartridges have also recently become popular.
These may include a pair of flat blades which can flex while remaining captivated alongside or within an integral segmented flexible blade support structure and guard bar. Two examples are shown in U.S. Pat. No. 4,409,735 to Cartwright et al. and U.S. Pat. No. 4,443,939 to Motta et al., the disclosures of which are hereby incorporated by reference.
The Uni-directional Razor Approach. In all of these conventional razors, the razor head is used for shaving in one direction only. For example, in shaving the user's face or legs, the user holds the handle of a conventional razor and moves the razor, with the blades contacting the skin, in one direction for cutting the hair extending from the skin. Normally, when the movement in one direction is completed, the user lifts the razor from the skin and brings it back to a point near the original starting position for moving the razor again in the same direction. These razors, whether of the fixed head-and-handle type, or of the fixed or pivoting cartridge-type, are uni-directional in operation, since the user strokes the razor in a single direction for cutting the hair.
Early Attempts At Bi-Directional Razors. I recognized that, in many instances, it would be desirable to have a bi-directional razor for more rapidly and efficiently shaving the user's face or arms or legs. That is, it would be convenient to provide a single-head razor construction which is usable for stroking first in one direction and then stroking backwards in the reverse direction without the necessity of the user rotating the entire razor by the handle 180.degree. degrees, so as to reduce the time and effort required in shaving. It is a primary object of this invention to provide several such bi-directional razors.
Limited efforts have been made to provide bi-directional razors, but with little success. U.S. Pat. No. 3,488,764 to Welsh discloses two razor blades mounted on a split head with a gap in between. Each blade strip is in effect mounted on its own head, and sharpened edges of two opposed blades face each other.
U.S. Pat. No. 4,501,066 to Sceberras discloses a dual-headed razor system having a single handle, with a pair of separately detachable razor heads separately connected to the handle. Each head has a pair of blades mounted on it. The razor system is said to be useful in shaving forwardly and rearwardly in to and fro strokes. So, like in the Welsh design, there are two heads, which means the Sceberras structure is wide and has limited maneuverability.
Further, using two heads adds significantly to the cost of the bi-directional razor approach by requiring two cartridge support structures and two cartridges. In addition, the working planes of the blades face one another. Thus, it appears that the Sceberras design on a relatively flat area of skin requires an unusual four-step shaving technique, namely: (a) tilt handle rearward to put the blades of forward head into optimum cutting position, (b) stroke the heads forward, (c) tilt handle forward to put blades of rearward head into optimum cutting position, and (d) stroke backwards.
Improvements In Bi-Directional Razors Are Still Needed. From my perspective, it would be desirable to provide improved bi-directional razor systems, structures and cartridges which allow the user to shave rapidly, effectively and efficiently. That can be accomplished, in accordance with my invention disclosed herein, by providing, on a single razor head, a plurality of blades facing away from one another. Such a razor head construction is usable in a bi-directional mode: that is, the razor head can be stroked in one direction and then reversed and stroked back in the opposite direction, without lifting or turning or repositioning the razor relative to the user's skin. The present invention is concerned with providing such bi-directional razor systems, heads and cartridges.
A first principal object of this invention is to provide several different single-head razor blade constructions, each of which can be used bi-directionally. Each razor construction features a single head which can be moved back-and-forth to shave in two opposite directions by the user who holds and uses the handle in his or her normal manner of holding and using a typical, conventional razor when shaving in one direction. Thus, the user is not required to hold or tilt the razors of my invention any differently than when holding and using a conventional razor. Further, it is a related object to provide such a bi-directional razor which may be used in two opposite directions without lifting or turning or tilting or repositioning the razor relative to the skin. Consequently, this object of the present invention is to provide a razor device which enables the user to simply move the razor back-and-forth, cutting hair in both directions, so as to substantially reduce the time and effort spent shaving.
A second principal object of the present invention is to provide for several different constructions of a economically made, bi-directional cartridge for a razor. In each construction, the object is to provide for either double pairs or two single blades mounted so that the cartridge can be manually removed from the razor and replaced with a fresh cartridge whenever the blades become sufficiently dull or the user otherwise wishes to change blades. Thus, the user may continually use the same razor handle by changing cartridges as desired.
A third principal object of the present invention is to provide a replaceable bi-directional cartridge structure which can be used on a conventional razor blade handle directly in place of a conventional uni-directional razor cartridge.
A related fourth principal object of the present invention is to provide compact bi-directional razor structures which can be used as effectively as present-day uni-directional razor heads to shave in tight locations such as on the face, near the nose and under the chin.
A fifth principal object of the present invention is to provide an improved manual shaving method, namely bi-directional shaving using a razor system having a single razor head supporting first and second pairs of blade strips arranged so that the sharpened blade edges of each set face away from the sharpened blade edges of the other set, whereby the handle of the razor need not be lifted, tilted or twisted as the shaving head or unit is moved back and forth in opposite directions to shave an area of the skin.
A sixth object of the present invention is provide a wet razor system that will more readily deliver a closer shave than conventional uni-directional dual-blade wet razor systems, by virtue of facilitating shaving the skin in two different directions, and by scraping and conditioning the skin to be shaved with one or two razor blade edges moving in a non-cutting direction.
A seventh object is to provide a wet shave razor blade system that stays sharper longer than a conventional uni-directional razor blade system by virtue of having twice as many shaving edges.
An eighth object is to provide several different constructions of bi-directional razor heads which are particularly economical to manufacture at a cost essentially equal to or slightly more than the cost of conventional uni-directional razor blade heads.
A ninth object is to provide a few different bi-directional razor blade constructions which are able to pivot or swivel while being used, in order to more readily follow the contour of the skin to be shaved.
A tenth object of the present invention is to provide a very stable shell-bearing razor head structure having improved skin-tracking action by virtue of an axis of head rotation being located above the working plane of the blades, that is beneath the skin to be shaved.
An eleventh object is to provide a few different bi-directional razor head structures especially designed to each have a very thin profile to facilitate shaving in tight locations, where the surface topography of the skin is concave and rapidly changing, and awkward to reach, like the inward curvature under the chin.
A twelfth object is to provide several different bi-directional razor blade structures wherein two pairs of blade strips both make effective use of a single glide or lubricant strip located between them.
A thirteenth object of the present invention is to provide bi-directional razor head constructions which feature all of the blade strips in substantially the same working plane.
A fourteenth object is to provide bi-directional razor structures each having two pairs of blade strips, with each pair being located in its own working plane facing away from and intersecting the other pair's working plane at an angle in the range of about five degrees up to about fifteen or more degrees.
A fifteenth object of the present invention is to provide a few different pivoting bi-directional razor structures wherein the two pairs of blade strips are each located in their own working plane facing away from the other working plane, with the two working planes intersecting one another at an angle of about twenty degrees or more, but with the pivot mechanism of razor so arranged that the two sets of blade strips during shaving operate in the same effective plane adjacent the user's skin.
A sixteenth object is to provide pivoting bi-directional razors having two working planes, in accordance with the fifteenth object, that are compactly and simply constructed, and have a thin profile.
A seventeenth object is to provide a few different bi-directional razor heads with either a pivot mechanism or a pivot-and-slide mechanism which facilitates changes in the orientation of the bi-directional head relative to the user's skin without the need for the user to lift, tilt or twist the handle of the razor as the shaving head is moved back and forth in opposite directions to shave an area of the skin.
An eighteenth object of the present invention is to provide a pivoting or swiveling razor head having an adjustment mechanism which allows the user to adjust the return-to-center force associated with the pivoting or swiveling action.
A nineteenth object is to provide a bi-directional razor head which is flexible and permits the two sets of blade strips to bend while being used so that the working pair of blade strips may more closely track the contours of the user's skin being shaved.
A twentieth object of the present invention is to provide a bi-directional razor construction where the razor blades are individually spring-loaded and may move independently in response to skin forces substantially perpendicular to the direction in which the razor head is being moved along the skin, so as to permit the individual blade strips to more closely conform to changing contours of a user's skin during shaving.
Still other objects of the present invention will become apparent from the descriptions of the preferred embodiments of the present invention which follow.